patch 8.0.1529: assert_equalfile() does not close file descriptors

Problem:    Assert_equalfile() does not close file descriptors. (Coverity)
Solution:   Close the file descriptors.
diff --git a/src/eval.c b/src/eval.c
index d891353..98288d6 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -8889,6 +8889,8 @@
 		}
 		++count;
 	    }
+	    fclose(fd1);
+	    fclose(fd2);
 	}
     }
     if (IObuff[0] != NUL)